The present invention relates to a spectro-photometer, and more particularly to a spectro-photometer which is equipped with a microcomputer for performing the arithmetic and control operation and can be used for both 2-wavelength spectro-photometry and 2-beam spectro-photometry.
Conventional spectro-photometers are usually provided with a calibration mechanism and a wavelength range changeover mechanism. A conventional spectro-photometer which employs a microcomputer to perform the calibrating operation, the wavelength-range changeover operation and the arithmetic operation on a photometric quantity obtained by the spectro-photometer and can be used for both 2-wavelength spectro-photometry and 2-beam spectro-photometry, is disclosed in, for example, a Japanese patent application entitled "Spectro-photometer" (Laid-open No. 120582/78).
In the conventional spectro-photometer of this kind, when it takes a few seconds to change over the wavelength range, an operator feels inconvenienced only a little. However, when the changeover of wavelength range requires several minutes, the operator will feel inconvenience in no little degree, since it is not clear how long the operator has to wait, or whether the suspension of operation in the spectro-photometer is caused by any trouble or changeover operation.